Three-dimensional memory device having on-pitch drain select gate electrodes and method of making the same

Abstract

A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate, and an array of memory opening fill structures extending through the alternating stack, an array of drain-select-level assemblies overlying the alternating stack and having a same two-dimensional periodicity as the array of memory opening fill structures, a first strip electrode portion laterally surrounding a first set of multiple rows of drain-select-level assemblies within the array of drain-select-level assemblies, and a drain-select-level isolation strip including an isolation dielectric that contacts the first strip electrode portion and laterally spaced from the drain-select-level assemblies and extending between the first strip electrode portion and a second strip electrode portion.